Acer palmatum, the Japanese Maple is a large shrub or small tree, often multistemmed, which is the most popular single species for autumn colour insuitable areas. It grows best in temperate regions in sheltered conditions with a humid atmosphere and acid soils. It is very variable and many varieties are grown which have different sizes and autumn colouring. Hillier lists nearly 40 named varieties. As the single most influential species for autumn colour, I judge it to be worth a page to itself.